• Environmental Analysis Health and Toxicology
• /
• v.20 no.4 s.51
• /
• pp.279-286
• /
• 2005

Earthworm (Eisenia fetida) acute toxicity test was carried out and ecological risk assessment in soil was performed with national monitoring data. 14 day - $LC_{50}$ of nonylphenol and bisphenol A were 288.1 mg/kg and 90.1 mg/kg, respectively. And NOECs of nonylphenol and bisphenol A were 250 mg/kg and 50 mg/kg, respectively. Significant weight decrement was appeared at 70 mg/kg of bisphenol A, however, nonylphenol at concentrations tested did not severe adverse effect on the weight decrement. The environmental monitoring has been carrying out by NIER since 1999. Exposure levels of nonylphenol in soil were ND$\sim$10.55 $\mu$g/kg and those of bisphenol A were ND$\sim$15.50$\mu$g/kg in National Monitoring data which had been performed from 2000 to 2004. The measured soil exposure level was applied to evaluate the environmental risk assessment. The values of PNEC for bisphenol A and nonylphenol were determined as 0.5 mg/kg and 2.5 mg/kg, respectively using the safety factors which were suggested in EU and OECD. The values of HQ (PEC/PNEC) were determined to be below I for bisphenol A and nonylphenol when the maximum exposure levels for bispheol A (15.50$\mu$g/kg) and nonylphenol (10.55$\mu$g/kg) were applied. Conclusively, the environmental risk assessment of bisphenol A and nonylphenol was not critical in soil.

• Women's Health Nursing
• /
• v.24 no.4
• /
• pp.423-434
• /
• 2018

Purpose: To investigate factors that affect behaviors of reducing exposure to endocrine disrupting chemicals (EDCs) in breastfeeding mothers. Methods: Subjects were 166 breastfeeding mothers who were recruited from January 25 to April 15, 2018. The questionnaire consisted of items associated with behaviors of reducing exposure to EDCs, attitude to behaviors of reducing exposure, subject norms of behavior of reducing exposure, and perceived behavior control. Data were analyzed by t-test, ANOVA, Pearson correlations, and stepwise multiple regression. Results: Factors influencing behaviors of reducing the exposure to EDCs were attitude toward behaviors of reducing exposure, perceived barrier, and period of lactation. The more positive the attitude toward behaviors of reducing exposure was, the lower the perceived barrier. The longer the feeding period, the higher the behaviors of reducing the exposure to EDCs. Conclusions: To enhance behaviors of reducing the exposure to EDCs, it is necessary to develop a positive educational program in breastfeeding department to improve attitude toward behaviors of reducing the exposure to EDCs, decrease perceived barrier, and increase the breastfeeding period.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.19 no.5
• /
• pp.723-737
• /
• 1995

The purposes of this study were to investigate 1) the difference of cognitive evaluation on body exposure of female clothing, ann 2) purchase frequency and intention of wearing according to demographic variables. The instrument of this study consisted of response scale and stimuli. Thirty three items of 7.point Likert scale were developed to measure cognitive evaluation of the people who responded. The stimuli were 7 types of clothing, differing exposure parts and style on line drawing. The sample included 450 subjects, consisting of 231 in Seoul and 219 in Chun-nam Province. Statistics applied for analysis were frequency, percentage, mean, standard deviation, correlation, t-test, F-test, Duncan's multiple range test, factor analysis. The Results were: 1. Constructing factors of cognitive evaluation consisted of elegance, sensuality, attraction, individuality. There were significant differences in every factor on each types of clothing. 2. The evaluation toward each types of clothing was influenced by the subjects' sex, age, and residence. 3. Purchase frequency and intention of female subjects' wearing were very low, and there were significant differences on demographic variables.

• Journal of Preventive Medicine and Public Health
• /
• v.28 no.1 s.49
• /
• pp.225-243
• /
• 1995

Benzidine Industry in Korea has started after Japan has banned its production in early 1970's, and it has been in operation in Korea for over 20 years. However, it is not known yet whether any bladder cancer has developed from benzidine exposure. This study was done to screen benzidine-exposed workers for bladder cancer, and to examine the feasibility of employing screening test at the workplace. All the workplaces that manufacture or use benzidine for more than 20 years in Korea have been covered in this study, and they include 2 benzidine manufacturing factories, 5 benzidine using factories, as well as 2 benzidine free factories as an outside control. In total, 516 workers were screened with urine stick test and urine cytology test for the evidence of hematuria and abnormal urothelial cells. Each worker was also asked about risk factors and symptoms of bladder cancer including past medical history, smoking, medication and occupational history Benzidine in the air was measured by personal and area sampling. Out of 516 screened workers, 84(16.3%) workers showed positive hematuria in urine stick test, and 7(1.4%) workers showed degenerative cells in urine cytology tests. Those workers with abnormal urine test results who have been exposed to benzidine fo more than 10 years were further screened, and, in total, 23 workers were examined with intra-venous pyelography and cystoscopy. None of those screened had any evidence of bladder cancer When workers with only past hematuria history were included in the positive hematuria group, 96(18.5%) had positive hematuria. On the multiple logistic regression analysis, positive hematuria was significantly associated with benzidine exposure, history of other occupations with elevated bladder cancer risk, pyuria and glycosuria. The association got stronger as direct benzidine exposure was accounted through individual task analysis, and as exposure duration was accounted with tenure analysis. For those with benzidine exposure with more than 10 years of tenure, the odds of having positive hematuria was elevated 2.14(95%C.I is 1.08 to 4.25) times more than for those without exposure. Even though bladder cancer was not detected for several limitations including short observation period, majority of studied workers with short latency, healthy worker effect, and low sensitivity of single screening test in a cross-sectional study, the study results suggest that hematuria screening is a feasible and very useful test for bladder cancer screening among benzidine exposed workers.

• The Journal of Advanced Prosthodontics
• /
• v.12 no.2
• /
• pp.89-99
• /
• 2020

PURPOSE. The effects of four different self-adhesive resin cement materials on cell viability and apoptosis after direct and indirect exposure were evaluated using different cell culture techniques. MATERIALS AND METHODS. Self-adhesive cements were applied to NIH/3T3 mouse fibroblasts by the extract test method, cell culture inserts, and dentin barrier test method. After exposure periods of 24 h and 72 h, the cytotoxicity of these self-adhesive materials was evaluated using the MTT assay (viability) and the Annexin-V-FITC/PI staining (apoptosis). RESULTS. The lowest cell viability was found in cells exposed to BeautiCem SA for 24 h in the extract test method. Cell viability was reduced to 70.6% compared to negative controls. After the 72 h exposure period, viability rate of cell cultures exposed to BeautiCem SA decreased more than 2- fold (29.5%) while cells exposed to RelyX U200 showed the highest viability rate of 71.4%. In the dentin barrier test method, BeautiCem SA induced the highest number of cells in apoptosis after a 24 h exposure (4.1%). Panavia SA Cement Plus was the material that caused the lowest number of cells in apoptosis (1.5%). CONCLUSION. The used self-adhesive cements have showed different cytotoxic effects based on the evaluation method. As exposure time increased, the materials showed more cytotoxic and apoptotic effects. BeautiCem SA caused significantly more severe cytotoxic and apoptotic effects than other cements tested. Moreover, cements other than BeautiCem SA have caused necrotic cell death rather than apoptotic cell death.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.31 no.4
• /
• pp.295-303
• /
• 2021

Objective: Paint manufacturing industry workers are exposed to various lung cancer carcinogenic substances including hexavalent chromium and crystalline silica. Studies have been conducted on lung cancer in Paint manufacturing industry workers and the concentration of hexavalent chromium in paint industry; however, the concentration of crystalline silica and hexavalent chromium and cases of lung cancer in a single Paint factory has never been reported in Korea. Methods: To determine whether the cancer was related to his work environment, we assessed the level of exposure to carcinogens during pouring and mixing talc and pigment. In addition, a mask fit test was performed for the worker. Results: Analysis of talc and silica bulk powder materials showed that crystalline silica (quartz) was 5% in talc and 100% in silica. The green and yellow pigments contained 87% and 92% of lead chromate, respectively. Our quantitative analysis of pigment powder samples showed that the hexavalent chromium contents quantified in the green and yellow pigment samples were 87% and 92%, respectively. In order to estimate his exposure level of hexavalent chromium, we measured a personal exposure level of hexavalent chromium for a worker in accordance with the National Institute for Occupational Safety and Health #7605 method. The results showed that the worker was exposed to the high level of hexavalent chromium (0.033 mg m-3). In addition, the talc powder also contained 5% quartz, and the worker's exposure level to respirable quartz exceeded OEL. As a result of the respiratory protection fit test for workers, the overall Fit Factor was '15' when wearing a second-grade mask and '25' when wearing a first-grade mask, significantly lower than the US Occupational Safety and Health Agency (OSHA) pass value of "100". Conclusion: Workers who pouring and mixing powder materials such as talc or colored pigments in paint manufacturing company may be exposed to high concentrations of carcinogenic substances. These findings indicate that it is necessary to local ventilation system inspection, safety and health education for employers and workers, and periodically monitoring and manage the working environment.

• Computers and Concrete
• /
• v.26 no.2
• /
• pp.115-125
• /
• 2020

To reduce the damage of concrete in fire, a new type of lightweight cinder aggregate concrete was developed due to the excellent fire resistance of cinder. To further enhance its fire resistance, Polypropylene (PP) Fibers which can enhance the fire resistance of concrete were also used in this type of concrete. However, the bond behavior of this new type of concrete after fire exposure is still unknown. To investigate its bond behavior, 185 specimens were heated up to 22, 200, 400, 600 or 800℃ for 2 h duration respectively, which is followed by subsequent compressive and tensile tests at room temperature. The concrete-rebar bond strength of C30 PP fiber-reinforced cinder concrete was subsequently investigated through pull-out tests after fire exposure. The microstructures of the PP fiber-reinforced cinder concrete and the status of the PP fibre at different temperature were inspected using an advanced scanning electron microscopy, aiming to understand the mechanism of the bonding deterioration under high temperature. The effects of rebar diameter and bond length on the bond strength of PP fiber-reinforced cinder concrete were investigated based on the test results. The bond-slip relation of PP fiber-reinforced cinder concrete after exposure at different temperature was derived based on the test results.

• Safety and Health at Work
• /
• v.3 no.3
• /
• pp.235-240
• /
• 2012

The objectives are to compare the airborne asbestos concentrations resulted from mitering of abestos cement roof sheets by a high-speed motor and a hand saw, and to monitor whether other workers near the test sites are vulnerable to the fibers exceeding the occupational exposure limit. Four test cases were carried out and altogether 7 personal and 4 area air samples were collected. The NIOSH method 7400 was employed for the air samplings and analysis. Using the phase contrast microscopy, fiber counting was conducted under Rule A. The study showed that the fiber concentration medians for personal air samples gathered from the two tools were 4.11 fibers/cc (ranged: 1.33-12.41 fibers/cc) and 0.13 fibers/cc (ranged: 0.01-5.00 fibers/cc) respectively. The median for the area samples was 0.59 fibers/cc (ranged: 0.14-3.32 fibers/cc). Comparing each study case, the concentration level caused by the high-speed motor saw was more than twice that of the hand saw. According to the area samples, the workers nearby the test site are at risk from high exposure to asbestos.

• Food Science and Industry
• /
• v.52 no.1
• /
• pp.52-59
• /
• 2019

The present article covers a brief introduction on how repeated exposure design can be utilized for developing new food products. A generic consumer taste test which measures consumer acceptance in one trial may have limitation in predicting long-term acceptability of a product. The article describes the changes in food preference and choice during the course of life from infants to elderly. Then, several possible theories that proposes to delineate the underlying mechanisms for acquiring the liking for food is introduced. The article also discusses general experimental design, case studies which adopted repeated exposure design, the limitations and rapid test methods to predict long-term acceptance.

• Journal of the Korea Concrete Institute
• /
• v.25 no.1
• /
• pp.45-51
• /
• 2013

Short beam tests of GFRP and CFRP specimens exposed to high temperature were conducted to measure the inter-laminar shear strength. For the phase I test, the exposure time and temperature were varied to measure reduction in the strength due to the applied conditions. As a results, the critical temperature was found to $270^{\circ}C$ for the both FRP reinforcements. The high temperature, which causes 50% loss of inter-laminar shear strength, is defined as the critical temperature in this study. It should be noted that the critical temperature for the inter-laminar shear strength is mainly dependent on resin properties not on fiber type. In the phase II test, the effect of exposure time was investigated at intervals of 0.25hour for the critical temperature. All test results demonstrate that the exposure time effect is not significant compared to the maximum exposure temperature, but it is not negligible and, moreover, is significant at the critical temperature.